Effects of off-sized cylindrical rollers on the static load distribution in a cylinder roller bearing

Author(s):  
Guanci Chen ◽  
Fanhai Mao ◽  
Baokun Wang

There are always some differences in the diameters of the rolling elements that are less than manufacturing tolerance, which are known as off-sized defects. These diameter differences of the rolling elements assumed to be with identical size in the traditional bearing analysis affect the load performance of the bearing greatly and make the evaluation of the load distribution in the bearing difficult. In this study, a static model was developed to investigate the effects of diameter differences among cylindrical rollers on the load performance in a bearing. In the model, the diameter and order of each roller were defined arbitrarily. Contact judgments between all the rollers and the raceways were done constantly in the solution process, so that compatibility of deformation of the rollers and raceways need not be considered, which was different from other traditional methods. The effects of roller off size and its arrayed order in the bearing on the load distribution were analyzed. It was found that the effect of one off-sized roller on the load distribution was serious. Also, equal space or ordinal array of the multiple or full off-sized rollers was much better than random array. Furthermore, the relative diameter of the rollers determined the load distribution in the bearing. This article can help to further study the dynamic performance of the bearing with the off-sized cylindrical roller in the future.

2019 ◽  
Vol 142 (3) ◽  
Author(s):  
Andreas Fingerle ◽  
Jonas Hochrein ◽  
Michael Otto ◽  
Karsten Stahl

Abstract Planetary gearboxes are becoming more popular due to their high-power density and potentially high efficiency. When the planet bearings are internally mounted, the body of the planet gear has to be hollow. The demand for large outer diameters due to high-load requirements might result in a small planet rim thickness. Depending on the rim thickness, its rigidity may become very low. Due to the low stiffness and the special load conditions caused by the double meshing, the deformation of the planet and its bearings are unique. In this paper, the influence of rim thickness on bearing load and lifetime is examined. The analysis is performed with a finite element method (FEM) model of a planet rim with a built-in cylindrical roller bearing. With the resulting planet deformation from the FEM calculation, the load distribution on the rolling elements in the bearing and the bearing lifetime according to ISO/TS 16281:2008 has been evaluated.


Author(s):  
Andreas Fingerle ◽  
Jonas Hochrein ◽  
Michael Otto ◽  
Karsten Stahl

Abstract Planetary gearboxes are becoming more popular due to their high power density and potentially high efficiency. When the planet bearings are internally mounted, the body of the planet gear has to be hollow. The demand for large outer diameters due to high load requirements might result in a small planet rim thickness. Depending on the rim thickness, its rigidity may become very low. Due to the low stiffness and the special load conditions caused by the double meshing, the deformation of the planet and its bearings are unique. In this paper, the influence of rim thickness on bearing load and lifetime are examined. The analysis is performed with an FEM model of a planet rim with a built-in cylindrical roller bearing. With the resulting planet deformation from the FEM calculation, the load distribution on the rolling elements in the bearing and the bearing lifetime according to ISO/TS 16281:2008 have been evaluated.


Author(s):  
W. Chen ◽  
R. Mills ◽  
R. S. Dwyer-Joyce

The load applied by each rolling element on a bearing raceway controls friction, wear and service life. It is possible to infer bearing load from load cells or strain gauges on the shaft or bearing housing. However, this is not always simply and uniquely related to the real load transmitted by rolling elements directly to the raceway. Firstly, the load sharing between rolling elements in the raceway is statically indeterminate, and secondly, in a machine with non-steady loading, the load path is complex and highly transient being subject to the dynamic behaviour of the transmission system. This study describes a method to measure the load transmitted directly by a rolling element to the raceway by using the time of flight (ToF) of a reflected ultrasonic pulse. A piezoelectric sensor was permanently bonded onto the bore surface of the inner raceway of a cylindrical roller bearing. The ToF of an ultrasonic pulse from the sensor to the roller–raceway contact was measured. This ToF depends on the speed of the wave and the thickness of the raceway. The speed of an ultrasonic wave changes with the state of the stress, known as the acoustoelastic effect. The thickness of the material varies when deflection occurs as the contacting surfaces are subjected to load. In addition, the contact stiffness changes the phase of the reflected signal and in simple peak-to-peak measurement, this appears as a change in the ToF. In this work, the Hilbert transform was used to remove this contact dependent phase shift. Experiments have been performed on both a model line contact and a single row cylindrical roller bearing from the planet gear of a wind turbine epicyclic gearbox. The change in ToF under different bearing loads was recorded and used to determine the deflection of the raceway. This was then related to the bearing load using a simple elastic contact model. Measured load from the ultrasonic reflection was compared with the applied bearing load with good agreement. The technique shows promise as an effective method for load monitoring in real-world bearing applications.


1973 ◽  
Vol 187 (1) ◽  
pp. 763-770 ◽  
Author(s):  
C. M. Taylor

Normally cylindrical roller bearings are employed to transmit purely radial loads. However, depending upon the configuration of lips or flanges on the rings, it is sometimes possible to carry an axial load. In certain applications, an axial load capability is essential. A significant feature in determining the performance of a cylindrical roller bearing under axial loading is the lubrication conditions existing between the lips and rolling elements. The paper describes a study of such conditions. The long-term aim of the work is to provide a basis for the design of cylindrical roller bearings to carry axial loads.


1980 ◽  
Vol 102 (2) ◽  
pp. 222-227 ◽  
Author(s):  
W. L. Bowen ◽  
C. P. Bhateja

The paper deals with the unique functional characteristics that the use of hollow rolling elements induce in a radial type cylindrical roller bearing. The ability to consistently and successfully preload these hollow rollers between the inner and the outer races together with, of course, the necessary but usual degree of precision of the bearing components, provides an effective control of the shaft run-out. This makes the bearing especially suitable for high precision applications. The roller preloading also eliminates the need for a roller guidance from a retainer which, combined with the lighter rollers, generally means higher speed capabilities. In addition to the inherent superior rotational accuracy of the hollow roller bearing, it is also demonstrated as to why, contrary to the common belief, the preloading ability of the hollow rollers results in significant stiffness improvements over, say, a corresponding solid roller bearing. The significance of the roller hollowness is discussed with regard to the stiffness, load capacity and life characteristics of this bearing. Finally, the suitability of the various lubrication systems for this bearing are discussed.


2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Simon Kabus ◽  
Claus B. W. Pedersen

The internal load distribution in rolling bearings has a high impact on the bearing fatigue life. This study presents a method to optimize roller bearing housing design in order to maximize the bearing fatigue life by ensuring an optimal internal load distribution. An FE-model of a cylindrical roller bearing utilizing nonlinear springs in the roller modeling is presented, which is capable of simulating the bearing load distribution efficiently. The optimal load distribution is achieved by specifying the desired internal load distribution as design constraints in a topology optimization of the bearing housing design. The superiority of the method is clearly demonstrated through case studies involving a cylindrical roller bearing, where it is shown that the fatigue life is increased and the bearing housing mass and roller contact misalignment is reduced.


1976 ◽  
Vol 98 (4) ◽  
pp. 538-543 ◽  
Author(s):  
A. Suzuki ◽  
A. Seireg

This study deals with an experimental investigation of a cylindrical roller bearing having annular rollers. Comparisons are made with a solid roller bearing having the same configuration and dimensions. Radial deformations and load distribution between rollers are measured under static load and compared with numerical solutions. Bearing temperature rise and roller wear are investigated in a specially designed tester. A radioactive tracing technique is utilized for the measurement of roller wear and proved to be reliable for wear detection. The results show several advantages of annular rollers over the solid rollers.


1973 ◽  
Vol 187 (1) ◽  
pp. 763-770
Author(s):  
C. M. Taylor

Normally cylindrical roller bearings are employed to transmit purely radial loads. However, depending upon the configuration of lips or flanges on the rings, it is sometimes possible to carry an axial load. In certain applications, an axial load capability is essential. A significant feature in determining the performance of a cylindrical roller bearing under axial loading is the lubrication conditions existing between the lips and rolling elements. The paper describes a study of such conditions. The long-term aim of the work is to provide a basis for the design of cylindrical roller bearings to carry axial loads.


2011 ◽  
Vol 480-481 ◽  
pp. 980-985
Author(s):  
Yan Shuang Wang ◽  
Ning Ning Jin ◽  
Hai Feng Zhu

A nonlinear dynamics analysis mathematical model for the high-speed cylindrical roller bearing was built up. Dynamic performance parameters were got by Newton - Raphson method . The rotational velocity regularities of rollers were analyzed at different radial loads. The distribution of minimum oil-film thickness and contact load between rollers and bearing ring raceway were obtained. The results showed that number of loaded rollers increased with the increase of radial loads at a certain speed. Rollers slip seriously at lower radial loads. The rotation speed was low. The minimum oil-film thickness between loaded rollers and inner raceways was less than that of outer raceways. The results were compared with the results of SHARBERTH and comparison was made with testing results. It showed that the dynamic characteristics analysis method of high speed cylindrical roller bearing was accurate, reliable,simple and convenient for practical engineering application.


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